1. Field of the Invention
The present invention relates generally to methods and systems providing communications services through wireless networks. Particular aspects of the invention relate to providing communications services through wireless networks connected to packet switched networks and methods of initiating a new session or handoff procedure when providing such services.
2. Discussion of the Related Art
Communications services have historically been provided over circuit-switched networks such as the Public Switched Telephone Network (PSTN), but now they can also be provided over packet switched networks, such as those supporting the Internet Protocol (IP). Many modern communication networks utilize a combination of wireless network equipment (such as cellular phones) and packet switched network equipment (usually network traffic routing equipment) compliant with one or more IP telephony standards such as, for example, the International Telecommunications Union (ITU) H.323 standard or the Internet Engineering Task Force (IETF) specifications.
There have been several proposals for a new 3rd generation of communications networks in which a packet switched network, compliant with one or more IP standards, is directly connected to a wireless access network. 3GPP Release ""00 (available at www.3gpp.org) uses the General Packet Radio Service (GPRS) packet switched network, a general description of which is documented in 3G TS 23.060 version 3.3.0. The GPRS packet switched network is specified for use with either a Universal Mobile Terrestrial System (UMTS) or a Global System for Mobile Communications (GSM) wireless access network. Another example of a 3rd generation communications network is the one in the cdma2000 specification (available at www.3gpp2.org), which includes both a cdma2000 wireless air interface and a cdma2000 packet data solution.
However, even though it may be preferable to use a particular packet switched network in a communications network (for example, a GPRS packet switched network may be preferable because it can serve as the transport layer for real-time applications such as streaming multimedia), there may be a problem using the preferred packet switched network in some circumstances because it is not specified for use, and is incompatible, with the particular wireless access network installed in the communications network (such as a cdma2000 wireless network). Since an installed wireless access network may consist of several thousands of cellular phones and associated base stations, it may not be cost effective or otherwise feasible to overcome the incompatibility or other problems by changing the wireless access network.
There is thus a disadvantage and a problem to be solved of allowing a communications network to include a packet switched network which is not specified for use with the wireless access network installed in the communications network. In particular, the solution to such a problem must allow subscribers of the wireless access network to access and roam between cellular networks and, preferably, access the same services available in their home network when they are visiting in other networks. Therefore, procedures must be developed between the packet switched network and the wireless access network for initiating a new session or providing a handoff for a subscriber of the wireless access network.
The present invention addresses the problems associated with communications networks discussed above. It broadly relates to systems and methods including one or more of the functions of providing, initiating, accessing, utilizing or managing internetworking functions for a communications network having both a wireless access network and a packet switched core network. A particular application of the invention relates to session or handoff methods in which a subscriber initiates a new session or visits a network other than their own network (roams).
The example embodiments of the invention offer a GPRS packet switched core network connected to a cdma2000 wireless access network so that packet data communications services can be easily provided A wireless gateway (WGW) is connected between the Serving GPRS Service Node (SGSN). The WGW uses the information from the cdma2000 wireless network to either initiate a session or perform a handoff of a subscriber.
One exemplary, non-essential, aspect of the invention is a method of triggering a new session or handoff procedure for a user equipment in a communications system having a second network connected to a first network. A first identifier from the first network is determined which indicates the location of the user equipment in the first network. The first identifier is provided to an entity connected to the first network and to the second network. The entity associates a second identifier of the second network with the first identifier of the first network. The first identifier indicates the location of the user equipment in the first network and the second identifier indicates the location of the user equipment in the second network. A second identifier of the second network is determined which indicates the location of the user equipment using said entity for associating the first identifier and the second identifier.
Another exemplary, non-essential aspect of the invention is a communications system having at least an access network, a core network, and a gateway connected between the access network and the core network. The communications system implements the method described in the previous paragraph to trigger the updating of an identifier in the core network indicating the location of a user equipment in the access network